above vs below ground water collection tank

i see about 5 or 6 months of freezing nights where i live. i'm setting up a rainwater collection system and am debating between above and below ground tanks.

from what i've read, an above ground in freezing weather will need its pump and pipes drained to prevent breakage. i'm assuming a below ground doesn't have this problem, but i do not have the money to bury a tank. does anyone have any experience/suggestions/tips with this?

I have freezing nights 9 months out of the year. My land is such that you would have to blast to make a hole for the tank. Like you, I didn't have the funds to bury the tank or the lines. So here's what I do.

All outside tanks are above ground. They are polyethylene, some open, some closed. They have been freezing every winter for 8 years with no problems. there are no fittings on them, due to the freezing. we drop submersible pumps into them whenever needed.

In my greenhouse the tanks are partially buried and have flat tops so I can grow flats of plants atop the tanks. The greenhouse is unheated in winter and gets down to 11F and still the big tanks (1800 gallons) do not freeze. These tanks are 3 feet below grade, 2 feet above grade. The 55 gallon barrels above ground in the greenhouse will get a 1/8" thick piece of ice on top that is easy to break.

I'm in the southwest and it is often above freezing in the daytime, even if the temperature drops by 40F degrees at night. So to move water around in winter, I have soft poly black orchard tubing 1" diameter. By late afternoon this black-colored line is thawed enough that you can get water flowing. So after a snowstorm we have a melt event and the water sits on top of the frozen ice in the cisterns. If I can pump it that day to where i want it, the frozen cistern doesn't fill up. my tanks are undersized at the collection points. To pump the water i use a 1/6hp submersible with 1" quick connects. it gets stored in the house at night and only comes out to pump the snow melt in winter. If I miss pumping a melt event, it tends to freeze that night and won't thaw until april.

by the end of winter I have 6000 gallons unfrozen in the greenhouse and 12000 gallons outside in cisterns as giant ice blocks. the inside water gives me enough to get the season started, and then later in spring the other tanks thaw and I have enough water for my crops.

tanks designed for burying are more expensive than above ground tanks. You can also consider partially burying the tanks. If the bottom is below frost line, it would be very difficult for the tank to freeze. might be cheaper than a complete burial, but still lines would need to be drained in winter.

I hope all this makes sense, feel free to ask questions.

Posts: 44

Location: West Coast of Canada

posted 8 years ago

Hi. First post here.

I have an above-ground water system. Last winter, we had two weeks where the temperature never got above freezing. I presume the water in the tanks froze, at least a few inches thick, but there was no damage.

When I installed the pipes, I made sure I had a drain valve at the lowest point in each run. I forgot one section, which I have to siphon dry in the fall. I'm planning to dig it up and install a drain valve. This works well if you are on a slope, where you can bring the drain line to the surface at a lower level. It would be a problem with buried pipes on level ground. If your piping is above ground, it shouldn't be a problem at all - just install the drain valve wherever the pipe is lowest.

Chris Dean

Posts: 108

Location: Central Texas

3

posted 8 years ago

thanks everyone for your responses. looks like above ground won't be a problem

NM Grower wrote: by the end of winter I have 6000 gallons unfrozen in the greenhouse and 12000 gallons outside in cisterns as giant ice blocks. the inside water gives me enough to get the season started, and then later in spring the other tanks thaw and I have enough water for my crops.

Does this supply all of your irrigation water?

Do you somehow harness the cold to cool in the summer?

Posts: 21

Location: NSW, Australia

posted 8 years ago

How about putting your tank:

1- In a sunny, all year round, spot and then 2- paint it BBQ black so it sucks up solar heat 3- Put it on top of hill/slope/elevation so cold air will run off

?

Posts: 94

Location: Colorado

posted 8 years ago

I have a 9000 gallon steel tank epoxy coated inside, and it is 9 feet across and 20 feet tall,

I know it freezes, up on some of it, I have done two things, one I put a bubbler in it, and painted it a medium brown, so the solar heat would help it,

we were near 0F at nights and below freezing during the day for a few weeks, most ever year, for the 10 years we have been using it, I am sure the out side has a few feet of ice on it, and my float needs replaced, (guessing the cable/cord) has been damaged from the ice falling or changing levels, so I know that ice has built up in the tank but since the water is moving and being pumped in and use out of it, it I have never had to abandon it during the winter months, on the piping I have a tunnel under it that I take the water out of the center of the tank and from the bottom,

I do hope to some time build a insulated enclose around it, with a solar type collector on the south on the south exposer, to add some more heat for the winter time.

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